The invention herein relates to alkali-resistant glass fiber compositions. More particularly it relates to such glass fiber compositions which are resistant to corrosive attack in an alkaline environment such as Portland cement.
For some years researchers have been working on glass compositions which could be made into fibers and the fibers in turn used as reinforcement in alkaline environments, notably Portland cement. A variety of different types of compositions have been suggested in patents and articles for use as alkali-resistant glass fibers. Most, however, have not proven to be practical because they have been difficult compositions to fiberize or have sacrificed other desirable properties for alkali resistance. Those which have become commercial have generally been compositions which have been high in the content of zirconia or other costly components. Among the more widely known compositions are those described in U.S. Pat. Nos. 3,783,092; 3,887,386 and 3,901,720, and British Patents Nos. 1,200,732 and 1,243,972 in the name of A. J. Majumdar.
It would definitely be advantageous to provide an alkali-resistant glass composition which could be readily fiberized and which would not require the use of large amounts of expensive materials such as zirconia.